This invention relates to dispersing agents for aqueous slurries. More particularly, this invention provides improved water-soluble dispersants that substantially increase the concentration of and/or reduce the viscosity of aqueous slurries of solid particulates such as coal, lignite, cement, gypsum, fillers (calcium carbonate), and other similar materials.
Water serves as an effective vehicle for preparing slurries of many particulate solids. A low solids content and/or a high viscosity often reduces the effective use of such slurries. Increasing the solids concentration of such slurries is seldom practical because of disproportionate increases in viscosity. Reducing the viscosity of such slurries via use of known dispersants has not always been technically or economically successful. For example, sulfonated alkyl-aromatic hydrocarbons, and condensation polymers of sulfonated naphthalene and formaldehyde have been effectively used as dispersants for aqueous coal and cement slurries, but use of such dispersants in these applications has been limited because of their relatively high cost.